1. The problem statement, all variables and given/known data If you have a simple Gaussian diagram of spherical shape, and arrows pointing out from the centre indicating [E] how do you know if [E] is constant or if it varies? Is it because the arrows are of slightly different lengths? (Though all eminating from the centre and going out past the circumference.) Does this indicate variation? Or would variation be indicated by arrows in different areas being more tightly together than other areas? Thank you.